A dual-carrier High Speed Packet Access (HSPA) system uses two adjacent carriers in the same band or two carriers in different bands. Compared to a single-carrier HSPA system, the dual-carrier HSPA system can double data transmission amount and smoothly provide a mass data traffic service and a real-time traffic service.
When the dual carrier is supported, frequency selectivity and multiuser diversity gain increase theoretically, compared to the single carrier supported. Accordingly, when users are optimally allocated to the dual carrier, load balancing for the dual carrier is achieved to thus accomplish more enhanced performance.
However, since the current dual-carrier HSPA system performs scheduling by considering only one frequency band as in the scheduling of the single-carrier HSPA, supporting the dual carrier may not be advantageous. For example, a dual carrier joint proportion fairness scheduling scheme is suggested as the scheduling method for the dual-carrier HSPA system. The joint proportion fairness scheduling determines a user priority for each carrier by expanding a Proportional Fairness (PF) scheduling scheme of the single-carrier HSPA system to the dual-carrier system, and thus can enhance the system performance compared to the single-carrier PF scheduling scheme.
Since the joint proportion fairness scheduling scheme determines the user's priority per carrier, the priority of one carrier does not affect the priority of the other carrier. However, the transmit data and the remaining resources depend on the carrier to which the user is first allocated in the actual environment. As a result, use of the dual carrier in such a manner may not be very advantageous.